The present invention is related to an adjustable arbor wheel mounting arrangement and more particularly to a device for more directly transmitting certain thrust forces on the wheel to the support frame. Such wheel mounting arrangement is preferably employed within a lift truck mast unit for maintaining transverse alignment of its movable upright within a supporting upright.
Conventional lift truck mast units include a stationary upright with one or more inner uprights nested for vertical rolling movement within it in order to allow a pair of lift fork members associated therewith to lift, carry and deposit a load as is desired. While a plurality of wheels or rollers are mounted for rolling engagement longitudinally within the beams or channels of these uprights, they usually are not adapted to fully transmit the side thrust forces. Consequently, in order to limit transverse movement of the inner upright relative to the supporting upright, side thrust rollers are commonly employed therebetween.
Prior side thrust roller mounting arrangements have for the most part utilized an arbor with a relatively fixed disposition on the lift mast unit. However, the variable dimensions of the uprights of these units require a custom fitting operation to insure that the side thrust rollers closely engage the opposite sides of the uprights. These arbors have heretofore been clampingly secured to the upright frame by one or more fasteners or bolts arranged in parallel with the axis of the arbor. Unfortunately, such construction is not well adapted to resist high side thrust forces normal thereto so that a large number of highly tightened fasteners are required. More recently, some arbors have been made with eccentric shafts so that they may be preadjusted to assure proper lateral contact of the roller with the upright. However, such eccentric arbor arrangements are complex and costly, suffer the disadvantage that the shaft is subject to shear loading, and require high torque on the fasteners thereof to obtain a sufficiently positive clamping force.
The present invention is directed to overcoming one or more of the problems as set forth above.
Accordingly, the present invention provides a novel adjustable arbor wheel arrangement including a support frame having a mounting surface, an arbor having an axis and an end mounting surface, a wheel rotatably mounted on the arbor, a plurality of fasteners for clamping the arbor end mounting surface against the mounting surface of the frame, and an abutment reaction device for directing thrust forces upon the wheel and substantially normal to the axis from the arbor to the frame. Such a wheel mounting arrangement is particularly advantageous in maintaining the lateral alignment between the uprights of a lift truck mast unit.